RECOVERY VOLTAGE TEST FOR OIL-PAPER INSULATIONINVESTIGATION

摘要

Diagnosis methods for quality assessment of large power transformers rise ?n importance, as deregulationrnof the energy market demands an improved life time management for expensive equipment. The state ofrninsulation is one of the primary parameters for the wear out of this kind of equipment. This paperrnproposes a measurement method for water concentration in transformers’ insulation using a computerrnadded test system. The method consists in time measurements of the depolarisation process of waterrnmolecules, which were firs oriented in a strong electric field applied between the windings and the case ofrnthe transformer. The magnitude and time response of this reorientation process depends on the water’srnlevel present ?n the insulation and it is a good merit figure for its quality.